The principle of multipactoring caused by secondary electron multiplier action is well known, having been described as early as 1954 in the April issue of the Journal of Applied Physics, by A. J. Hatch and H. B. Williams, in an article entitled, "Secondary Electron Resonance". This phenomenon occurs when the coefficient of secondary electron emission between two opposed surfaces across which a cycling voltage is maintained, exceeds unity. Furthermore, if one of the opposed surfaces is perforated, the electrons that are allowed to escape constitute a useful beam current. Additionally, due to the resonant nature of the multipactor process, the output beam will be bunched and thus a non-thermionic electron source becomes available for many applications such as signal amplification . A more recent publication describing the multipactor effect comprises an article entitled, "The Multipactor Effect", which was published by W. J. Gallagher in the IEEE Transactions On Nuclear Science, Vol. NS-26, No. 3, June, 1979, pp. 4230-4232.
One known microwave amplifier using multipaction to produce periodically bunched electrons is U.S. Pat No. 3,312,857, which issued to P. T. Farnsworth, on Apr. 4, 1967. The invention described there discloses an electron discharge device comprising a cavity having two spaced apart field defining and electron-emitting surfaces with means for applying an alternating electromagnetic field to the space between the surfaces. The spacing between the surfaces and the amplitude and period of the field are such as to produce phase focusing of electrons in the space between the surfaces. One of the surfaces has an electron emitting aperture from which bunches of phase-focussed electrons are emitted. The device also includes a means for accelerating and directing electron bunches periodically emitted from the aperture along a predetermined path as well as means for absorbing the kinetic energy from the bunches as they traverse a predetermined drift region.
An RF activated, non-thermionic electron gun employing the principles of multipactor is further disclosed in a publication entitled, "The Multipactor Electron Gun", by William J. Gallagher, which appeared in the Proceedings of The IEEE on January, 1969, at pp. 94-95.
Accordingly, it is an object of the present invention to provide an improvement in high frequency electronic devices.
It is another object of the invention to provide an improvement in non-thermionic electron devices.
It is yet another object of the invention to provide an improvement in devices operating in accordance with the phenomenon of secondary electron resonance.
It is still another object of the invention to provide improvement in multipactor type devices for use with microwave or millimeter wave signals.